1. Field of the Invention
Aspects of the present invention relate to an image forming apparatus and method thereof.
2. Description of the Related Art
Generally, an image forming apparatus, such as a laser printer, performs a halftone process for each pixel representing an image when displaying a gray scale image in monochrome. The halftone process is a method for representing a gray scale image, by adjusting the number of dots constituting the pixels. For example, if the number of black dots is from 0 to 255, a image can be produced having 256 different gray values.
If an image forming apparatus enhances the quality or characteristics of the halftone-processed image, edges of the image can be blurred. An ‘edge’ is a boundary area between pixels of an image, for example, a discontinuous line of a gray level pattern.
There are methods to correct blurring edges. In one such method, for example, an edge is detected after applying a binary system to an input image, and an edge map is drawn. A gray value of an area in which an edge exists, is changed using the edge map. A diffused gray value is compensated by changing the gray value. Alternatively, a line width is increased when the brightness of a line of an input image exceeds a threshold value, and when the line width is less than a threshold value.
However, the above methods have various problems. For example, when edges are detected after applying a binary system to an image, edges exceeding a certain brightness may not be detected, because a compensating position and/or a gray value of the undetected edge may differ from a detection position of the input image. In addition, the gray value and the shape of the edge are changed between input and output of the image. Furthermore, an edge is not compensated when a negative hairline of an image is exclusively considered. Accordingly, these methods may not improve resolution of an image.